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EBSD on the Nacre Structure of a Pearl (Hyriopsis cumingii) with 100 nm Resolution - Busting a Myth

Nacre of pearls and mollusc shells is a hybrid nano composite of aragonite (CaCO3) platelets and biopolymers. The colorful luster of nacre is due to the aragonite platelet thickness which is close to the wavelength of visible light. Further, the hybrid composite nanostructure lends nacre extraordinary mechanical properties. The biopolymer component provides flexibility and tensile strength while, the mineral component is essential for high elastic modulus, compressive and bending strength, as well as hardness and abrasive resistance. The fracture toughness of nacre is orders of magnitude higher than that of pure CaCO3 (Mayer, 2005, Barthelat, 2010). Due to the large electron penetration depth in nacre at the conventionally used 20 kV acceleration voltage in SEM/EBSD investigations, a spatial resolution in the order of 1 micron has been reported. (Schmahl et al., 2009, Goetz et al., 2009). This is insufficient to resolve nacreous nanostructures. This application note illustrates how the resolution of EBSD data can be significantly enhanced when low acceleration voltage is used.

*Please note, this application note refers to NordlysNano & X-Max 80. This has since been upgraded to Symmetry S3 & Ultim Max respectively.

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